Semi-levered shrink landing gear

ABSTRACT

An aircraft includes a landing gear having a shock strut, an outer sleeve at least partially surrounding the shock strut, and a shrink mechanism coupled to both the outer sleeve and the shock strut, where the shrink mechanism moves the shock strut relative to the outer sleeve. The shrink mechanism includes a shaft rotatably coupled to the outer sleeve, an anchor arm coupled to the shaft, a shrink arm coupled to the shaft, the shrink arm and the anchor arm being coupled to the shaft so as to rotate as a unit with the shaft about a shaft rotation axis, relative to the outer sleeve, at least 180° when the anchor arm is coupled to the structure within the wing of the aircraft, and a shrink link rotatably coupled to the shrink arm, the shrink link being configured to rotatably couple to the shock strut.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of U.S.patent application Ser. No. 15/611,844 filed on Jun. 2, 2017 (now U.S.Pat. No. 10,800,516 issued on Oct. 13, 2020), the disclosure of which isincorporated herein by reference in its entirety.

BACKGROUND 1. Field

The aspects of the present disclosure generally relate to an aircraftlanding gear and more particularly to semi-levered shrink landing gear.

2. Brief Description of Related Developments

Aircraft with one or more of large engine fan diameters, long fuselages,long wings, and specialized under-aircraft payload, for example, may usea tall landing gear structure to provide ground clearance to the engineand sufficient clearance during take-off. For example, during take-off,the nose of an aircraft rotates upward and the tail rotates downward toachieve an angle-of-attack at take-off. The longer the aircraft, thetaller the landing gear is to achieve the take-off angle-of-attack. Thetaller the landing gear, the higher the angle-of-attack. Integratinglonger/taller landing gear structures into the aircraft may imposeexpensive design constraints on the aircraft and also may add weight,which in turn requires greater fuel consumption by the aircraft. Inaddition, lengthening the landing gear increases the static height ofthe aircraft and may require the use of over-wing slides integrated intothe aircraft and/or a larger wheel well (noting larger wheel wells maynot be possible without redesigning the aircraft).

Landing gear structures on aircraft generally employ an OLEO (i.e.,pneumatic air-oil hydraulic) shock strut, in which a piston compresses avolume that includes both a compressible gas and a substantiallyincompressible liquid. Generally, such landing gear structures include amain fitting (e.g., an outer tube), a piston (e.g., an inner tube), anda sliding tube cylinder, thus involving three tubes/cylinders. A landinggear structure that includes an OLEO shock strut may be compressed intoa retracted configuration for stowage in the wheel well during flight.However, achieving the retracted configuration may require compressingthe compressible gas to an undesirably high pressure. Additionally, suchlanding gear including mechanisms to compress the OLEO shock strut tendto be heavy and complex, thus creating potential disadvantages fromaircraft efficiency, maintenance, and manufacture standpoints.

Generally, to avoid compressing the OLEO shock strut, to enableretracting the landing gear into the wheel well, pivoting truck leversare employed with a linkage mechanism that pivots the truck lever toshorten a length of the landing gear upon retraction of the landinggear. The linkage mechanism is generally coupled to the structure of thelanding gear, which landing gear structure drives the linkage mechanismto pivot the truck lever.

SUMMARY

The following is a non-exhaustive list of examples, which may or may notbe claimed, of the subject matter according to the present disclosure.

One example of the subject matter according to the present disclosurerelates to a shrink mechanism for use with a landing gear of anaircraft, the landing gear including an outer sleeve at least partiallysurrounding a shock strut, the shrink mechanism comprising: a shaftrotatably coupled to the outer sleeve about a shaft rotation axis, theshaft being disposed perpendicular to a centerline of the shock strut;an anchor arm coupled to the shaft, the anchor arm being configured tocouple to a structure within a wing of the aircraft; a shrink armcoupled to the shaft, the shrink arm and the anchor arm being coupled tothe shaft so as to rotate as a unit with the shaft about the shaftrotation axis; and a shrink link rotatably coupled to the shrink arm,the shrink link being configured to rotatably couple to the shock strut.

Another example of the subject matter according to the presentdisclosure relates to a landing gear for use on an aircraft, the landinggear comprising: an outer sleeve; a shock strut positioned at leastpartially within the outer sleeve; and a shrink mechanism coupled to theouter sleeve and the shock strut, the shrink mechanism being configuredto move the shock strut relative to the outer sleeve, the shrinkmechanism including a shaft rotatably coupled to the outer sleeve abouta shaft rotation axis, the shaft being disposed perpendicular to acenterline of the shock strut; an anchor arm coupled to the shaft, theanchor arm being configured to couple to a structure within a wing ofthe aircraft; a shrink arm coupled to the shaft, the shrink arm and theanchor arm being coupled to the shaft so as to rotate as a unit with theshaft about the shaft rotation axis; and a shrink link rotatably coupledto the shrink arm, the shrink link being configured to rotatably coupleto the shock strut.

Still another example of the subject matter according to the presentdisclosure relates to an aircraft comprising: a landing gear including ashock strut and an outer sleeve at least partially surrounding the shockstrut; and a shrink mechanism coupled to the outer sleeve and the shockstrut, the shrink mechanism being configured to move the shock strutrelative to the outer sleeve, the shrink mechanism including a shaftrotatably coupled to the outer sleeve about a shaft rotation axis, theshaft being disposed perpendicular to a centerline of the shock strut,an anchor arm coupled to the shaft, the anchor arm being configured tocouple to a structure within a wing of the aircraft, a shrink armcoupled to the shaft, the shrink arm and the anchor arm being coupled tothe shaft so as to rotate as a unit with the shaft about the shaftrotation axis, and a shrink link rotatably coupled to the shrink arm,the shrink link being configured to rotatably couple to the shock strut.

Still another example of the subject matter according to the presentdisclosure relates to a method of operating a landing gear of anaircraft, the method comprising: rotating the landing gear about atrunnion axis of rotation, the trunnion axis of rotation being definedby an outer sleeve of the landing gear; and moving a shock strutrelative to the outer sleeve with a shrink mechanism, where the outersleeve at least partially surrounds the shock strut and the shrinkmechanism includes: a shaft rotatably coupled to the outer sleeve abouta shaft rotation axis, the shaft being disposed perpendicular to acenterline of the shock strut, an anchor arm coupled to the shaft, theanchor arm being configured to couple to a structure within a wing ofthe aircraft, a shrink arm coupled to the shaft, the shrink arm and theanchor arm being coupled to the shaft so as to rotate as a unit with theshaft about the shaft rotation axis, and a shrink link rotatably coupledto the shrink arm, the shrink link being configured to rotatably coupleto the shock strut.

Still another example of the subject matter according to the presentdisclosure relates to an anti-rotation linkage for use with a landinggear having an outer sleeve and a shock strut positioned at leastpartially within the outer sleeve, the anti-rotation linkage comprising:a connector plate coupled to the shock strut; and an anti-rotation linkassembly coupled to both the outer sleeve and the connector plate, theanti-rotation link assembly being configured to maintain the shock strutin a fixed rotational orientation relative to the outer sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described examples of the present disclosure in generalterms, reference will now be made to the accompanying drawings, whichare not necessarily drawn to scale, and wherein like referencecharacters designate the same or similar parts throughout the severalviews, and wherein:

FIG. 1A is a schematic illustration of an aircraft in accordance withaspects of the present disclosure;

FIG. 1B is a schematic illustration of the aircraft of FIG. 1 inaccordance with aspects of the present disclosure;

FIG. 1C is a schematic illustration of a conventional landing gear;

FIG. 2A is a schematic perspective view of a portion of a landing gearin accordance with aspects of the present disclosure;

FIG. 2B is a schematic top view of the landing gear of FIG. 2A inaccordance with aspects of the present disclosure;

FIG. 2C is a schematic front view of the landing gear of FIG. 2A inaccordance with aspects of the present disclosure;

FIG. 2D is a schematic side view of the landing gear of FIG. 2A inaccordance with aspects of the present disclosure;

FIG. 3 is a schematic side view of the landing gear of FIG. 2A inaccordance with aspects of the present disclosure;

FIG. 3A is a schematic illustration of a portion of the landing gear ofFIG. 2A in accordance with aspects of the present disclosure;

FIG. 4 is a schematic side view of the landing gear of FIG. 2A inaccordance with aspects of the present disclosure;

FIG. 5 is a schematic side view of the landing gear of FIG. 2A inaccordance with aspects of the present disclosure;

FIG. 6 is a schematic side view of the landing gear of FIG. 2A inaccordance with aspects of the present disclosure;

FIG. 7 is a flow diagram of a method in accordance with aspects of thepresent disclosure;

FIG. 8A is a schematic front view of a portion of the aircraft of FIG.1A in accordance with aspects of the present disclosure;

FIG. 8B is a schematic side view of a portion of the aircraft of FIG. 1Ain accordance with aspects of the present disclosure;

FIG. 9A is a schematic side view of a portion of the landing gear ofFIG. 2A in accordance with aspects of the present disclosure; and

FIG. 9B is a schematic side view of a portion of the landing gear ofFIG. 2A in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

Referring to FIGS. 1A-1C, an aircraft 100 generally includes an airframe100F, wings 322, main landing gear 200A, and nose landing gear 200B.During take-off, the nose 100N of the aircraft 100 rotates upward andthe tail 100T rotates downward to achieve an angle-of-attack AOA attake-off. The longer the aircraft 100, the longer/taller the landinggear is to achieve the angle-of-attack AOA. Lengthening the landing gearcan cause at least a couple of issues. For example, if the aircraft 100is more than six (6) feet (1.8 meters (m)) off of the ground, theaircraft 100 must include over-wing slides integrated into the aircraft100. Further, longer landing gear has an associated a larger wheel well,which may require costly redesign of the aircraft 100. At least somelanding gear is designed to extend and retract to obtain the benefits oflonger landing gear while maintaining the same landing gear length onthe ground (e.g., conventional ride height) and in the wheel wellcompared to conventional landing gear CSS (FIG. 1C) having a singleshock strut (which includes an outer cylinder CSSO and an inner cylinderCSSI and a single wheel axle CWA coupled to the inner cylinder).Generally, the landing gear designed to extend and retract to obtain thebenefits of longer landing gear, while maintaining the convention rideheight, includes complex mechanisms within the shock strut to extend andretract the landing gear to achieve the additional landing gear lengthat take-off. The more complex mechanisms within the landing gear allowall of the landing gear components to be contained within the landinggear (e.g., the complex mechanisms are coupled only to the structure ofthe landing gear). For example, such complex mechanisms may include ashrink link that attaches to a walking beam of the landing gear. Whilethis simplifies the interface to the airframe 100F structure, it canalso limit the amount of rotation of the shrink link, thus limiting anamount of retraction/extension of the shock strut provided by the shrinklink.

Referring to FIG. 1A, the aspects of the present disclosure overcome thedeficiencies of conventional landing gear as well as improve on thelanding gear designed to extend and retract to obtain the benefits oflonger landing gear (e.g., with complex shrink mechanisms carried by andcoupled only to components of the landing gear). For example, theaspects of the present disclosure provide a landing gear 200A thatincludes a shrink mechanism that increases a length of the landing gear200A when the landing gear 200A is extended and decreases the length ofthe landing gear 200A when the landing gear is retracted into a stowageposition within the aircraft 100. The shrink mechanism of the landinggear 200A couples (or grounds) to the wing structure rather than beingcoupled (or grounded) to another component of the landing gear 200A(e.g., such as a retract actuator or walking beam of the landing gear)as will be described in greater detail herein. Coupling the shrinkmechanism of the present disclosure to the wing structure independent of(e.g., outside of) the landing gear 200A provides the shrink mechanismwith an increased rotation (compared to shrink mechanisms grounded tothe landing gear structure) so that a shock strut coupled to the shrinkmechanism can be retracted/extended a greater distance compared to adistance of retraction/extension of the shrink mechanisms grounded tothe landing gear structure. The shrink mechanism in accordance with theaspects of the present disclosure, by virtue of the increased rotationof the shrink mechanism, can be used with a shortened conventional shockstrut, rather than having complex inner workings in the shock strut.

The landing gear 200A, in accordance with the aspects of the presentdisclosure, includes a semi-levered (trailing arm) suspension thatincludes a conventional OLEO (a pneumatic air-oil hydraulic) shock strutthat is extended and retracted as a unit by a shrink mechanism, wherethe shrink mechanism is grounded to a structure of the respective wing322 of the aircraft 100. Grounding the shrink mechanism to the structureof the respective wing 322 provides the shrink mechanism with at least180 degrees of rotation for extending and retracting the OLEO shockstrut. The landing gear 200A including the shrink mechanism, inaccordance with the aspects of the present disclosure, provides alanding gear 200A that is designed to extend and retract to obtain thebenefits of longer landing gear, while maintaining the conventional rideheight and conventional length in the wheel well (when compared to,e.g., conventional landing gear CSS illustrated in FIG. 1C), with onlyone OLEO shock strut. As such, the landing gear 200A with the shrinkmechanism of the aspects of the present disclosure can provide forhigher reliability and less complexity compared to other attempts atincreasing the length of aircraft landing gear with complex mechanisms.As a further example, of the reduced complexity that can be provided bythe aspects of the present disclosure, the shrink mechanism of thelanding gear 200A is a two-dimensional mechanism (e.g., the shrinkmechanism acts substantially only in a single plane of the aircraft100). The landing gear of the present disclosure also avoids or reduceslarge bending loads introduced into the OLEO shock strut.

In another aspect of the present disclosure, the shrink mechanismenables a top-of-strut seal to reduce or substantially eliminate anydebris accumulation within the landing gear 200A.

The aspects of the present disclosure may also provide the landing gear200A with an anti-rotation linkage 366 (see, e.g., FIG. 4 ) thatprevents the OLEO shock strut 210 (FIG. 4 ) from rotating with respectto the shrink mechanism 300 (see, e.g., FIG. 4 ) and, for example, anouter sleeve 310 (see, e.g., FIG. 4 ) of the landing gear (as describedin greater detail herein). More specifically, the anti-rotation linkage366 couples to both the outer sleeve 310 and an outer cylinder 368 (see,e.g., FIG. 4 ) of the shock strut to prevent relative rotation of theOLEO shock strut 210, the outer sleeve 310 and the shrink mechanism 300.It is noted that coupling of the shrink link to the walking beam orretract actuator can prevent relative rotation between the sleeve andshock strut; however, the anti-rotation linkage in the presentdisclosure can be used on more conventional landing gear independent ofthe walking beam and retract actuator.

Referring now to FIGS. 2A, 2B, 2C, and 2D, as described above, thelanding gear 200A includes a shrink mechanism 300 coupled to (e.g.,grounded) to any suitable structure 320 of a respective wing 322, wherethe structure 322 is disposed within the wing and is separate anddistinct from the landing gear 200. For example the structure 320 is arear spar 350 of the respective wing 322. In accordance with aspects ofthe present disclosure, the landing gear 200A includes an outer sleeve310, a shock strut 210, and the shrink mechanism 300. The outer sleeve310 forms an opening 354 that extends along longitudinal axis 316. Theouter sleeve 310 is coupled to a trunnion 342 of the landing gear 200Awhere the trunnion 342 is coupled to the structure 320 of the wing 322for rotation about rotation axis 344. In one aspect, the outer sleeve310 and the trunnion 342 are integrally formed as a one piece monolithicmember. The shock strut 210 includes an outer cylinder 368 and an innercylinder 374, and is disposed at least partially within the opening 354so that a longitudinal axis 316′ of the shock strut 210 is substantiallycoincident with the longitudinal axis 316 of the outer sleeve 310. Thelongitudinal axis 316, 316′ is considered a centerline of the shockstrut 210. The opening 354 is configured so that the shock strut 210linearly moves along the longitudinal axis 316 within the opening 354 aswill be described herein. A walking beam 390 and retract actuator 392are coupled to trunnion 342 in a conventional manner to retract thelanding gear 200A to a stowage position within the aircraft 100 (FIG. 1).

In accordance with the aspects of the present disclosure, the shrinkmechanism 300 is provided for use with the landing gear 200A of theaircraft 100 (FIG. 1 ), where the landing gear 200A includes the outersleeve 310, which at least partially surrounds the shock strut 210. Theshrink mechanism 300 includes a shaft 312, a shrink link 326, and a rod340. The shaft 312 is rotatably coupled to the outer sleeve 310 in anysuitable manner for rotation about a shaft rotation axis 314. The shaftrotation axis 314 is spatially arranged relative to the outer sleeve 310so as to be substantially perpendicular to the longitudinal axis 316 ofthe outer sleeve 310, as well as the longitudinal axis 316′ of the shockstrut 210. The shaft 312 includes an anchor arm 318 that is coupled tothe shaft 312 in any suitable manner. In one aspect, the anchor arm 318is integrally formed with the shaft as a one piece monolithic member.The anchor arm 318 is configured to couple to the structure 320 withinthe respective wing 322 of the aircraft 100 in any suitable manner, suchas through the rod 340. The shaft 312 also includes a shrink arm 324that is coupled to the shaft 312 in any suitable manner. In one aspectthe shrink arm 324 is integrally formed with the shaft 312 as a onepiece monolithic member. As such, the coupling between each of theshrink arm 324 and the anchor arm 318 with the shaft 312 is such thatboth the shrink arm 324 and the anchor arm 318 rotate as a unit with theshaft 312 about the shaft rotation axis 314. The shrink arm 324 andanchor arm 318 may be arranged at any suitable angle β relative to oneanother, where the angle β may depend on a grounding location of the rod(e.g. inboard, outboard, etc.) on the structure 320 of the respectivewing 322.

The rod 340 includes a first end 340E1 and a second end 340E2 that islongitudinally spaced from the first end 340E1. The first end 340E1 ofthe rod 340 is pivotally coupled to the anchor arm 318. The second end340E2 of the rod 340 is pivotally coupled to the structure 320 of therespective wing 322 in any suitable manner. For example, the wingstructure 322 may include any suitable stanchion or protrusion 341 towhich the second end 340E2 of the rod 340 is pivotally coupled. It isnoted that while the rod 340 extends from the anchor arm 318 in anoutboard direction, in other aspects the rod 340 may extend in aninboard direction for coupling to the structure 320 of the respectivewing 322 in a manner substantially similar to that described above. Inaccordance with the aspects of the present disclosure, the shrinkmechanism 300 is coupled to the structure 320 of the respective wing322, via the rod 340, independent of both the walking beam 390 and theretract actuator 392. This allows for increased rotation of the shaft312 (compared to shrink mechanisms carried solely by the landing gearand grounded to the walking beam and/or retract actuator) which resultsin an increase in linear translation of the shock strut 210 (again,compared to shrink mechanisms carried solely by the landing gear andgrounded to the walking beam and/or retract actuator) within the outersleeve 310 for extending and retracting the shock strut relative to theouter sleeve 310.

Still referring to FIGS. 2A-2D, the shrink link 326 includes a first end326E1 that is rotatably coupled to the shrink arm 324. The shrink link326 also includes a second end 326E2 that is longitudinally spaced fromthe first end 326E1, where the second end 326E2 is configured torotatably coupled to the shock strut 210 in any suitable manner. Forexample, the outer cylinder 368 of the shock strut 210 is configured forrotatably coupling with the second end 326E2 of the shrink link 326. Aswill be described in greater detail below, the shrink arm 324 rotatesabout shaft rotation axis 314 so that the shrink link 326, coupled tothe shrink arm 324, travels within the outer sleeve 310 to extend andretract the landing gear 200A (e.g., to extend and retract the shockstrut 210 relative to the outer sleeve 310).

As described above, the shrink mechanism 300 is a two-dimensionalmechanism in that the shrink mechanism 300 acts substantially in asingle plane 358. For example, substantially all movements of the shrinkmechanism 300 exist within the plane 358 defined by the inboard/outboarddirections and the longitudinal axis 316′ of the shock strut 210 (whichlongitudinal axis 316′ is coincident with the longitudinal axis 316 ofthe outer sleeve 310). Configuring shrink mechanism 300 so that themovements of the shrink mechanism are in a single plane 358 may reducebending moments exerted on the landing gear 200A by the shrink mechanism300, and may reduce bending moments within the shrink mechanism 300itself. In addition, the planar, two-dimensional, nature of the shrinkmechanism 300 may reduce bearing misalignment requirements in the jointsof the shrink mechanism 300 (e.g., the pivotal/rotational couplingsbetween the different links 340, 318, 324, 326 of the shrink mechanism300). The planar, two-dimensional, nature of the shrink mechanism 300may also minimize an integration volume (e.g., a volume reserved for theshrink mechanism 300 within the aircraft 100) of the shrink mechanism300.

Referring now to FIG. 3 , a side view of the landing gear 200A isillustrated with the shock strut 210 substantially fully compressed. Itis noted that the shrink mechanism 300 is rotated 90 degrees relative tothe rest of the landing gear 200A for clarity purposes only (e.g. sothat the movement of the shrink mechanism can be illustrated). As can beseen in FIG. 3 , a coordinate system (e.g. UP, Inbound) is illustratedfor shrink mechanism 300 while the coordinate system (e.g. Up, Forward)is illustrated for the rest of the landing gear 200A. As describedabove, the landing gear 200A is a semi-levered landing gear thatincludes the outer sleeve 310, the trunnion 342, and a shock strut 210disposed at least partially within the opening 354 of the outer sleeve310. The landing gear 200A further includes a connector plate 372, ananti-rotation linkage 366, a truck link 220, and a strut arm 376. Theouter cylinder 368 of the shock strut 210 forms part of a semi-levermechanism 370 and the semi-lever mechanism 370 forms part of theanti-rotation linkage 366. The connector plate 372 and truck link 220also form parts of the semi-lever mechanism 370.

The connector plate 372 is coupled to the outer cylinder 368 of theshock strut 210 in any suitable manner. In one aspect, the connectorplate 372 is integrally formed with the outer cylinder 368 as a onepiece monolithic member. In one aspect, referring to FIG. 3A, theconnector plate 372 is a forked shaped member that includes fork tines372T that straddle at least a portion of the truck link 220. In otheraspects, the connector plate 372 may have any suitable configuration.

Still referring to FIG. 3 , the anti-rotation linkage 366 is coupled toboth the outer sleeve 310 and the shock strut 210. The anti-rotationlinkage 366 is configured to maintain wheels 204 coupled to the shockstrut 210 in a predetermined rotational orientation (e.g. about thelongitudinal axis 316, 316′) relative to the outer sleeve 310. Theanti-rotation linkage 366 further includes an anti-rotation linkassembly 382. The anti-rotation link assembly 382 includes two or morelinks. For example, the anti-rotation link assembly 382 includes a firstlink 384 and a second link 386 (in other aspects the anti-rotation linkassembly 382 may have more than two links). The first link 384 isrotatably coupled at a first end 384E1 to the outer sleeve 310 in anysuitable manner about pivot axis AX1. A second end 384E2 of the firstlink 384 is rotatably coupled to a first end 386E1 of the second link386. A second end 386E2 of the second link 386 is rotatably coupled tothe connector plate 372 in any suitable manner about pivot axis AX2. Assuch, the anti-rotation link assembly 382 rotationally fixes (i.e.,prevents relative rotation) the connector plate 372 (and the outercylinder 368) to the outer sleeve 310.

The truck link 220 is pivotally coupled to the connector plate 372 aboutpivot axis AX3 in any suitable manner. The truck link 220 also includesa wheel axis AX4, along which a single wheel axle 378 is located. Thewheel(s) 204 rotate about the wheel axis AX4 on the wheel axle 378. Thetruck link 220 is also pivotally coupled to inner cylinder 374 of theshock strut 210. For example, a first end 376E1 of a strut arm 376 ispivotally coupled to the truck link 220 about pivot axis AX5. The strutarm 376 also includes a second end 376E2 longitudinally spaced from thefirst end 376E1. The second end 376E2 is pivotally coupled to the innercylinder 374 about pivot axis AX6. It is noted that the pivot axis AX5is positioned between the pivot axis AX3 and the wheel axis AX4 suchthat an arc AX5R through which the pivot axis AX5 travels during trucklink 220 rotation (about pivot axis AX3) is localized about thelongitudinal axis 316, 316′ (e.g. the pivot axis AX5 is substantiallyin-line with the longitudinal axis 316, 316′ throughout the arc AX5R oftravel). As such, the force F exerted by the truck link 220, through thestrut arm 376, on the shock strut 210 acts substantially along thelongitudinal axis 316, 316′ thereby reducing or eliminating any momentloads on the shock strut 210. As described above, because theanti-rotation link assembly 382 prevents rotation of the connector plate372, the anti-rotation link assembly 382 also prevents rotation of thetruck link 220 about the longitudinal axis 316, 316′.

As described above, the shock strut 210 moves linearly (e.g.,reciprocates) within the outer sleeve 310 along the longitudinal axis316, 316′. For example, the opening 354 of the outer sleeve 310 includesa cylindrical guide surface 380 (see also FIG. 2A) configured to engageand guide sliding movement of the outer cylinder 368 of the shock strut210 to extend and retract the landing gear 200A, e.g., to extend andretract the shock strut 210 relative to the outer sleeve 310. Generallythe opening 354 in the outer sleeve 310 and the shock strut 210 arecylindrical (e.g., tubular) so that the shock strut 210 may rotatewithin the opening 354 relative to the outer sleeve 310. Further, theouter cylinder 368 and inner cylinder 374 of the shock strut 210 arealso cylindrical such that the inner cylinder 374 and outer cylinder 368may rotate relative to one another (and the outer sleeve 310). Theanti-rotation linkage 366 is configured to maintain each of the outercylinder 368, the inner cylinder 374, and the wheel(s) 204 in a fixedrotational orientation (about the longitudinal axis 316, 316′) relativeto the outer sleeve 310. For example as described above, the connectorplate 372 is coupled to the outer cylinder 368 so that the connectorplate 372 and the outer cylinder 368 cannot rotate relative to eachother. The rotational orientation of the outer sleeve 310 is fixed byvirtue of being coupled to the airframe 100F (FIG. 1 ) by the trunnion342. The anti-rotation link assembly 382, as described above, couplesthe outer sleeve 310 to the shock strut 210 (e.g. the anti-rotation linkassembly 382 is coupled to the outer cylinder 368 through the connectorplate 372). As such, the anti-rotation link assembly 382 preventsrelative rotation between the outer sleeve 310 and the outer cylinder368 of the shock strut 210. Rotation of the truck link 220 about thelongitudinal axis 316, 316′ is also prevented by the anti-rotation linkassembly 382 by virtue of the pivotal coupling between the truck link220 and the connector plate 372, only providing rotation of the trucklink 220 about pivot axis AX3. As such, the anti-rotation linkage 366prevents rotation of the wheel(s) 204 about the longitudinal axis 316,316′ and maintains the wheel(s) 204 in a predetermined rotationalorientation (e.g., about the longitudinal axis 316, 316′) relative tothe outer sleeve 310 (and the airframe 100F). It is noted that the strutarm 376 prevents relative rotation between the inner cylinder 274 (whichis rotationally fixed to the truck link 220, relative to thelongitudinal axis 316, 316′, by the strut arm 376) of the shock strut210 and the outer cylinder 368 (which is rotationally fixed to the outersleeve, relative to the longitudinal axis 316, 316′, by theanti-rotation linkage 366) of the shock strut 210.

Referring to FIGS. 3 and 4 , as described above, the landing gear 200Ais a semi-levered landing gear that includes semi-levered mechanism 370.The semi-levered mechanism 370 includes the outer cylinder 368(including the connector plate 372), the truck link 220, and the strutarm 376. In one aspect, the semi-levered mechanism 370 provides atrailing arm configuration that provides an amount of trail TR (see FIG.4 ) relative to, for example, the longitudinal axis 316, 316′. In oneaspect, the amount of trail TR may be about 10 inches (25.4 centimeters(cm)), while in other aspects the amount of trail TR may be more or lessthan about 10 inches (25.4 cm). The trail TR provided by the aspects ofthe present disclosure may provide for movement of the center of gravityCG (FIG. 1 ) of the aircraft 100 (FIG. 1 ) towards the tail 100T during,for example, aft loading of the aircraft 100 when the aircraft is on theground. For example, the trail TR may reduce or substantially eliminateany moment generated by an offset between the center of gravity CG andthe reaction force provided by the landing gear 200A when the center ofgravity CG is moved aft towards the tail 100T.

Referring to FIGS. 2D, 3, 4, 5, 6, and 7 , an exemplary operation of thelanding gear 200A and the shrink mechanism 300 will be described. It isnoted that FIG. 3 illustrates the landing gear 200A in an un-stowedposition (e.g., outside the wheel well for take-off, landing and taxiingof the aircraft 100 (FIG. 1 )) with the shock strut 210 in asubstantially fully compressed configuration. FIG. 4 illustrates thelanding gear 200A in an un-stowed position (e.g., outside the wheel wellfor take-off, landing and taxiing of the aircraft 100 (FIG. 1 )) withthe shock strut 210 in under compression, on the ground, with a static1G load applied. FIG. 5 illustrates the landing gear 200A in anun-stowed position (e.g., outside the wheel well for take-off, landingand taxiing of the aircraft 100 (FIG. 1 )) with the shock strut 210substantially fully extended to provide additional landing gear height Xduring take-off and landing of the aircraft 100 (FIG. 1 ). In oneaspect, the additional landing gear height X combined with the travel ofthe shock strut 210 provides the landing gear 200A with about 28 inches(71.1 cm) of travel, while in other aspects the amount of travel may bemore or less than about 28 inches (71.1 cm). FIG. 6 illustrates thelanding gear 200A in a stowed position (e.g., inside the wheel well ofthe aircraft 100 (FIG. 1 )) with the shock strut 210 substantially fullyextended but retracted within the outer sleeve 310 to shorten a lengthof the landing gear 200A. It is noted that in each of FIGS. 3-6 theshrink mechanism 300 is rotated 90 degrees relative to the rest of thelanding gear 200A for clarity purposes only (e.g., so that the movementof the shrink mechanism can be illustrated). As can be seen in FIG. 3-6, a coordinate system (e.g., “UP, Inbound” with the landing gear 200A inan un-stowed positon and “UP, Inboard” with the landing gear 200A in astowed position) is illustrated for shrink mechanism 300 while thecoordinate system (e.g., Up, Forward) is illustrated for the rest of thelanding gear 200A.

Referring to FIGS. 2D and 3 , with the landing gear 200A in theun-stowed position, the shrink mechanism 300 locks the shock strut 210in an extended position relative to the outer sleeve 310 so that theouter cylinder 368 of the shock strut extends a distance X1 from theouter sleeve 310. For example, the outer sleeve 310 is rotatably coupledto the wing 322 as described above (FIG. 7 , Block 720) and the anchorarm 318 is coupled to the structure 320 of the wing 322 (FIG. 7 , Block730) as described above. As can be seen best in FIG. 2D, with the outersleeve 310 rotatably coupled to the wing 322 and the anchor arm 318coupled to the structure 320, the shrink mechanism 300 forms anover-center lock that holds the shock strut 210 in the extended positionrelative to the outer sleeve 310. For example, as the landing gear 200Ais moved from the stowed position 801 (FIG. 8A) to the un-stowedposition 800 (FIG. 8A) the shaft 312 and the outer sleeve 310 rotaterelative to each other such that the shaft 312 is rotated relative tothe outer sleeve 310 in direction RB. Relative rotation between theshaft 312 and the outer sleeve 310 continues until a stop surface 324Sof the shrink arm 324 contacts a corresponding stop surface 310S of theouter sleeve 310. As can be seen in FIG. 2D, a pivot axis AX7 at whichthe shrink arm 324 is rotatably coupled to the shrink link 326 isrotated passed a centerline OCL extending between the axis 314 and thepivot axis AX8 (about which the shrink link 326 is pivotally coupled tothe outer cylinder 368).

As the shock strut 210 extends from being substantially fullycompressed, as illustrated in FIG. 3 , to the static 1G ride heightposition illustrated in FIG. 4 , the inner cylinder 374 moves indirection 400A causing the truck link 220 to rotate in direction RC. Thestatic ride height position illustrated in FIG. 4 provides the landinggear 200A with a length L1 that, in turn, may provide available wheel204 travel to absorb bumps, etc. during taxiing of the aircraft 100(FIG. 1 ). As the weight of the aircraft 100 is reduced (via liftprovided by the wings 322 (FIG. 1 )) during take-off, the inner cylinder374 of the shock strut extends further in direction 400A relative to theouter cylinder 368 as shown in FIG. 5 . This further extension of theinner cylinder 374 causes rotation of the truck link 220 in direction RCto provide the landing gear with additional height X at take-off. Theadditional height X provides the landing gear with an extended length L2at take-off.

Referring again to FIG. 2D as well as FIG. 6 , after take-off thelanding gear 200A is moved to the stowed position 800 (FIG. 8A) throughactuation of the retract actuator 392 (FIG. 2A). Retraction of thelanding gear 200A to the stowed position 800 (FIG. 8A) rotates thelanding gear 200A about the trunnion axis of rotation 344 (FIG. 7 ,Block 700). As described above, rotating the landing gear 200A about thetrunnion axis of rotation 344 causes relative rotation between the shaft312 and the outer sleeve 310. When the landing gear 200A is moved to thestowed position 800 (FIG. 8A), the shaft 312 rotates relative to theouter sleeve 310 in direction RA by virtue of the coupling between theshaft 312 and the structure 320 (FIG. 2A) of the wing 322 (FIG. 2A)provided by the rod 340. The relative rotation of the shaft 312 indirection RA also causes the shrink arm 324 to rotate in direction RA.The rotation of the shrink arm 324 in direction RA moves the shrink link326 in direction 400B within the outer sleeve 310 to retract the shockstrut 210. Because the shrink link 326 is coupled to the outer cylinder368 of the shock strut 210, the shock strut 210 also moves relative tothe outer sleeve 310 in direction 400B (FIG. 7 , Block 710) so that theshock strut 210 is retracted into the outer sleeve 310 by the distanceX1. As can be seen in FIG. 6 , the retraction of the shock strut 210into the outer sleeve 310 by the distance X1 provides the landing gear200A with a stowed length of L3 which is smaller than the length L2. Itis noted that when the landing gear is stowed, the shock strut issubstantially uncompressed. Moving the landing gear 200A from the stowedposition 800 (FIG. 8A) to the un-stowed position 801 (FIG. 8A) occurs insubstantially the reverse manner from that described above.

Referring to FIGS. 1A, 8A, and 8B, as the aircraft 100 accelerates downa runway, the wings 322 create lift. The lift created by the wings 322reduces the weight of the aircraft 100 applied to the landing gear 200A.The reduction in weight of the aircraft 100 applied to the landing gear200A causes the shock strut 210 to extend or uncompress. Extension ofthe shock strut 210 causes relative movement between an inner cylinder374 (FIG. 3 ) of the shock strut 210 and outer cylinder 368 of the shockstrut 210. The relative movement of the inner cylinder 374 and outercylinder 368 during extension of the shock strut 210 causes the trucklever 220 to rotate in direction RC (FIG. 5 ) to a takeoff heightposition, as seen best in FIG. 8B (see also FIG. 5 ), which may providethe aircraft 100 with additional height X relative to the static rideheight A (see also FIG. 8A) of the aircraft 100 (e.g., the ride height Ais increased by height X at the takeoff height of the landing gear200A). The additional height X, which is greater than the amount ofextension provided by the shock strut 210 alone, provides for apredetermined angle of rotation θ of the aircraft 100 relative to theground GR, as seen in FIG. 7B, upon takeoff and provides for apredetermined angle of rotation a (e.g., angle of attack) of theaircraft 100 relative to ground GR upon landing. Here the angles ofrotation θ, α are increased compared to takeoff and landing angles ofrotation θ′, α′ of the aircraft 100 when equipped with a conventionalsingle axle landing gear CSS (see FIGS. 1C and 8A—noting that in FIG. 8Athe conventional landing gear CSS and landing gear 200A are illustratedside by side for exemplary purposes only, otherwise the landing gear200A and the conventional landing gear would be arranged along a commoncenterline CL relative to the airframe 100F centerline ACL) as seen inFIG. 7B where wheel travel is limited only by an amount of travel of theconventional shock strut CSS and the distance Z between a ground contactpatch of the wheel(s) 204 and a tail skid pad 860 of the aircraft 100remains the same for the aircraft 100.

Because the landing gear 200A can be coupled to the airframe 100F insubstantially the same location as the conventional landing gear, andbecause the shock strut 210 is retractable into the outer sleeve 310,the landing gear 200A may fit within a conventional wheel wellsubstantially without any modification to the aircraft 100 design. Inother aspects, the landing gear may be retrofit to existing aircraft.For example, referring to FIG. 8A, a wheel retract path 820 for theconventional landing gear having shock strut CSS is illustrated comparedto a wheel retract path 821 for the landing gear 200A. As can be seen inFIG. 8 , while the wheel retract paths 820, 821 are separated by adistance corresponding to the additional height X of the landing gear200A when the landing gears are in an un-stowed position (such as duringtakeoff and landing), the wheel retract paths converse to a common path850 within the wheel well allowing the landing gear 200A to fit withinan existing wheel well. In addition, as can be seen in FIG. 8A, thelanding gear 200A may provide the aircraft 100 with the same static rideheight A as the conventional landing gear with shock strut CSS.

Referring now to FIGS. 9A and 9B, the landing gear 200A may also includea hinged door 352 that is configured to engage and substantially seal atop of the opening 354 of the outer sleeve 310 with the landing gear200A in the un-stowed position 801 (FIG. 8A). The hinged door 352 isslaved with at least one linkage of the shrink mechanism 300 in anysuitable manner. For example, the hinged door 352 includes a first doorportion 694 and a second door portion 396 that are pivotally coupled toeach other with hinge 356. The first door portion 694 may be coupled to,for example, the shrink arm 324 so as to be spatially fixed with respectto the shrink arm 324. For example, the coupling between the shrink arm324 and the first door portion 394 is such that the shrink arm 324 andthe first door portion 394 rotate as a single unit about the shaftrotation axis 314. The second door portion 396, being hinged to thefirst door portion also rotates with the shrink arm 324 about the shaftrotation axis 314; however, as the shrink arm 324 rotates in direction900 a free end 396EF of the second door portion 396 engages an uppersurface 310US of the outer sleeve 310 adjacent the opening 354.

As the shrink arm 324 continues to rotate in direction 900, theengagement between the free end 396EF causes relative rotation betweenthe first door portion 394 and the second door portion 396 so that thehinged door flattens to substantially form a seal with the upper surface310US of the outer sleeve thereby substantially sealing the opening 354.To maintain the seal, the second door portion 396 is biased relative toone or more of the first door portion 394 and the shrink arm 324 in anysuitable manner, such as by any suitable biasing member. For example,the biasing member 398 may be a tension spring that couples the seconddoor portion 396 to the shrink arm 324 to bias the second door portionin direction 902. In other aspects the biasing member 398 may be atorsion spring disposed at the hinge 356 to bias the second door portionin direction 902. The biasing member 398 also causes the hinged door tofold on itself when the shrink arm 324 is rotated in direction 324, suchas when shock strut 210 is retracted into the outer sleeve 310 duringthe landing gear 200A stowage. For example, as the shrink link 324rotates in direction 901 the biasing member 398 causes the second doorportion 396 to rotate in direction 902 about the hinge 356 to fold thesecond door portion 396 relative to the first door portion 394. Thefolding of the hinged door 352 upon stowage reduces the amount of spaceoccupied by the hinged door 352 so that, for example, the hinged doorfits within existing wheel wells of the aircraft 100 (FIG. 1 )substantially without modification to the wheel well.

The following are provided in accordance with the aspects of the presentdisclosure:

A1. A shrink mechanism for use with a landing gear of an aircraft, thelanding gear including an outer sleeve at least partially surrounding ashock strut, the shrink mechanism comprising: a shaft rotatably coupledto the outer sleeve about a shaft rotation axis, the shaft beingdisposed perpendicular to a centerline of the shock strut; an anchor armcoupled to the shaft, the anchor arm being configured to couple to astructure within a wing of the aircraft; a shrink arm coupled to theshaft, the shrink arm and the anchor arm being coupled to the shaft soas to rotate as a unit with the shaft about the shaft rotation axis; anda shrink link rotatably coupled to the shrink arm, the shrink link beingconfigured to rotatably couple to the shock strut.

A2. The shrink mechanism of paragraph A1, wherein the anchor arm iscoupled to the structure with a rod.

A3. The shrink mechanism of paragraph A1, wherein the shock struttravels within the outer sleeve to extend and retract the landing gear.

A4. The shrink mechanism of paragraph A1, wherein the shrink arm rotatesabout shaft rotation axis and the shrink link travels within the outersleeve to extend and retract the landing gear.

A5. The shrink mechanism of paragraph A1, wherein the outer sleeve isintegrally formed as on piece with a landing gear trunnion and whereinthe landing gear trunnion is rotatably coupled to the wing.

A6. The shrink mechanism of paragraph A1, wherein the anchor arm isconfigured to couple to a rear spar within a wing of the aircraft.

A7. The shrink mechanism of paragraph A1, wherein the structure withinthe wing is separate and distinct from the landing gear.

A8. The shrink mechanism of paragraph A1, further comprising a doorcoupled to the shrink arm, the door is configured to seal an opening inthe outer sleeve with the landing gear in an extended position.

A9. The shrink mechanism of paragraph A8, wherein the door comprises ahinged door configured to engage the outer sleeve for sealing theopening.

A10. The shrink mechanism of paragraph A1, wherein the shrink linkmechanism is configured to act in a single plane that is transverse to arotation axis of a landing gear trunnion of the landing gear.

B1. A landing gear for use on an aircraft, the landing gear comprising:an outer sleeve; a shock strut positioned at least partially within theouter sleeve; and a shrink mechanism coupled to the outer sleeve and theshock strut, the shrink mechanism being configured to move the shockstrut relative to the outer sleeve, the shrink mechanism including ashaft rotatably coupled to the outer sleeve about a shaft rotation axis,the shaft being disposed perpendicular to a centerline of the shockstrut, an anchor arm coupled to the shaft, the anchor arm beingconfigured to couple to a structure within a wing of the aircraft, ashrink arm coupled to the shaft, the shrink arm and the anchor arm beingcoupled to the shaft so as to rotate as a unit with the shaft about theshaft rotation axis, and a shrink link rotatably coupled to the shrinkarm, the shrink link being configured to rotatably couple to the shockstrut.

B2. The landing gear of paragraph B1 wherein the anchor arm is coupledto the structure with a rod.

B3. The landing gear of paragraph B1 wherein the shock strut travelswithin the outer sleeve to extend and retract the landing gear.

B4. The landing gear of paragraph B1 wherein the shrink arm rotatesabout shaft rotation axis and the shrink link travels within the outersleeve to extend and retract the landing gear.

B5. The landing gear of paragraph B1 wherein outer sleeve is integrallyformed as one piece with a landing gear trunnion and wherein the landinggear trunnion is rotatably coupled to the wing.

B6. The landing gear of paragraph B1, wherein the anchor arm isconfigured to couple to a rear spar within a wing of the aircraft.

B7. The landing gear of paragraph B1, wherein the structure within thewing is separate and distinct from the landing gear.

B8. The landing gear of paragraph B1, further comprising a door coupledto the shrink arm, the door is configured to seal an opening in theouter sleeve with the landing gear in an extended position.

B9. The landing gear of paragraph B8, wherein the door comprises ahinged door configured to engage the outer sleeve for sealing theopening.

B10. The landing gear of paragraph B1, wherein the shrink link mechanismis configured to act in a single plane that is transverse to a rotationaxis of a landing gear trunnion of the landing gear.

B11. The landing gear of paragraph B1, further comprising ananti-rotation linkage coupled to both the outer sleeve and the shockstrut, the anti-rotation linkage being configured to maintain wheelscoupled to the shock strut in a predetermined orientation relative tothe outer sleeve.

B12. The landing gear of paragraph B11, wherein the landing gear is asemi-levered landing gear where an outer cylinder of the shock strutforms part of a semi-lever mechanism and the semi-lever mechanism formspart of the anti-rotation linkage.

B13. The landing gear of paragraph B12, wherein the semi-leveredmechanism includes a connector plate coupled to the outer cylinder ofthe shock strut.

B14. The landing gear of paragraph B13, wherein the semi-lever mechanismincludes a truck link pivotally coupled to the both the connector plateand an inner cylinder of the shock strut.

B15. The landing gear of paragraph B14, further comprising a strut armcoupling the inner cylinder to the truck link.

B16. The landing gear of paragraph B14, wherein the truck link includesa single wheel axle.

B17. The landing gear of paragraph B1, wherein the outer sleeve includesa cylindrical guide surface configured to engage and guide slidingmovement of an outer cylinder of the shock strut to extend and retractthe landing gear.

B18. The landing gear of paragraph B1, wherein the shock strut comprisesan OLEO (a pneumatic air-oil hydraulic shock absorber) shock strut.

C1. An aircraft comprising: a landing gear including a shock strut andan outer sleeve at least partially surrounding the shock strut; and ashrink mechanism coupled to the outer sleeve and the shock strut, theshrink mechanism being configured to move the shock strut relative tothe outer sleeve, the shrink mechanism including a shaft rotatablycoupled to the outer sleeve about a shaft rotation axis, the shaft beingdisposed perpendicular to a centerline of the shock strut, an anchor armcoupled to the shaft, the anchor arm being configured to couple to astructure within a wing of the aircraft, a shrink arm coupled to theshaft, the shrink arm and the anchor arm being coupled to the shaft soas to rotate as a unit with the shaft about the shaft rotation axis, anda shrink link rotatably coupled to the shrink arm, the shrink link beingconfigured to rotatably couple to the shock strut.

C2. The aircraft of paragraph C1 wherein the anchor arm is coupled tothe structure with a rod.

C3. The aircraft of paragraph C1 wherein the shock strut travels withinthe outer sleeve to extend and retract the landing gear.

C4. The aircraft of paragraph C1 wherein the shrink arm rotates aboutshaft rotation axis and wherein shrink link travels within the outersleeve to extend and retract the landing gear.

C5. The aircraft of paragraph C1 wherein outer sleeve is integrallyformed with a landing gear trunnion and wherein the landing geartrunnion is rotatably coupled to the wing.

C6. The aircraft of paragraph C1, wherein the anchor arm is configuredto couple to a rear spar within a wing of the aircraft.

C7. The aircraft of paragraph C1, wherein the structure within the wingis separate and distinct from the landing gear.

C8. The aircraft of paragraph C1, further comprising a door coupled tothe shrink arm, the door is configured to seal an opening in the outersleeve with the landing gear in an extended position.

C9. The aircraft of paragraph C8, wherein the door comprises a hingeddoor configured to engage the outer sleeve for sealing the opening.

C10. The aircraft of paragraph C1, wherein the shrink link mechanism isconfigured to act in a single plane that is transverse to a rotationaxis of a landing gear trunnion of the landing gear.

C11. The aircraft of paragraph C1, further comprising an anti-rotationlinkage coupled to both the outer sleeve and the shock strut, theanti-rotation linkage being configured to maintain wheels coupled to theshock strut in a predetermined orientation relative to the outer sleeve.

C12. The aircraft of paragraph C11, wherein the landing gear is asemi-levered landing gear where an outer cylinder of the shock strutforms part of a semi-lever mechanism and the semi-lever mechanism formspart of the anti-rotation linkage.

C13. The aircraft of paragraph C12, wherein the semi-levered mechanismincludes a connector plate coupled to the outer cylinder of the shockstrut.

C14. The aircraft of paragraph C13, wherein the semi-lever mechanismincludes a truck link pivotally couple to both the connector plate andan inner cylinder of the shock strut.

C15. The aircraft of paragraph C14, further comprising a strut armcoupling the inner cylinder to the truck link.

C16. The aircraft of paragraph C14, wherein the truck link includes asingle wheel axle.

C17. The aircraft of paragraph C1, wherein the outer sleeve includes acylindrical guide surface configured to engage and guide slidingmovement of an outer cylinder of the shock strut to extend and retractthe landing gear.

C18. The aircraft of paragraph C1, wherein the shock strut comprises anOLEO (a pneumatic air-oil hydraulic shock absorber) shock strut.

D1. A method of operating a landing gear of an aircraft, the methodcomprising: rotating the landing gear about a trunnion axis of rotation,the trunnion axis of rotation being defined by an outer sleeve of thelanding gear; and moving a shock strut relative to the outer sleeve witha shrink mechanism, where the outer sleeve at least partially surroundsthe shock strut and the shrink mechanism includes: a shaft rotatablycoupled to the outer sleeve about a shaft rotation axis, the shaft beingdisposed perpendicular to a centerline of the shock strut, an anchor armcoupled to the shaft, the anchor arm being configured to couple to astructure within a wing of the aircraft, a shrink arm coupled to theshaft, the shrink arm and the anchor arm being coupled to the shaft soas to rotate as a unit with the shaft about the shaft rotation axis, anda shrink link rotatably coupled to the shrink arm, the shrink link beingconfigured to rotatably couple to the shock strut.

D2. The method of paragraph D1, further comprising coupling the anchorarm to the structure with a rod.

D3. The method of paragraph D1, wherein the shock strut travels withinthe outer sleeve to extend and retract the landing gear.

D4. The method of paragraph D1, wherein the shrink arm rotates aboutshaft rotation axis and the shrink link travels within the outer sleeveto extend and retract the landing gear.

D5. The method of paragraph D1, further comprising rotatably couplingthe outer sleeve to the wing about a trunnion axis of rotation such thatthe outer sleeve is integrally formed with a landing gear trunnion.

E1. An anti-rotation linkage for use with a landing gear having an outersleeve and a shock strut positioned at least partially within the outersleeve, the anti-rotation linkage comprising: a connector plate coupledto the shock strut; and an anti-rotation link assembly coupled to boththe outer sleeve and the connector plate, the anti-rotation linkassembly being configured to maintain the shock strut in a fixedrotational orientation relative to the outer sleeve.

E2. The anti-rotation linkage of paragraph E1, wherein the anti-rotationlink assembly maintains wheels coupled to the shock strut in apredetermined orientation relative to the outer sleeve.

E3. The anti-rotation linkage of paragraph E1, wherein the landing gearis a semi-levered landing gear having a truck link pivotally coupled tothe connector plate and at least one wheel rotatably coupled to thetruck link.

E4. The anti-rotation linkage of paragraph E3, wherein the shock strutincludes an outer cylinder movably disposed within the outer sleeve andan inner cylinder that is movable relative to the outer cylinder, theconnector plate being coupled to the outer cylinder of the shock strut.

E5. The anti-rotation linkage of paragraph E4, wherein the truck link ispivotally coupled to both the connector plate and the inner cylinder ofthe shock strut.

E6. The anti-rotation linkage of paragraph E5, further comprising astrut arm coupling the inner cylinder to the truck link.

E7. The anti-rotation linkage of paragraph E1, wherein a single wheelaxle is coupled to the shock strut.

E8. The anti-rotation linkage of paragraph E1, wherein the outer sleeveincludes a cylindrical guide surface configured to engage and guidesliding movement of an outer cylinder of the shock strut.

E9. The anti-rotation linkage of paragraph E1, wherein the shock strutcomprises an OLEO shock strut.

E10. The anti-rotation linkage of paragraph E1, wherein the linkassembly comprises a first scissors link coupled to the outer sleeve;and a second scissors link coupled to the first scissors link and theconnector plate to connect to the outer sleeve to the shock strut.

E11. A landing gear comprising: the outer sleeve; the shock strut; andthe anti-rotation linkage of any one of paragraphs E1 to E10.

E12. The landing gear of paragraph E11 further comprising the shrinkmechanism of any one of paragraphs A1 to A10.

In the figures, referred to above, solid lines, if any, connectingvarious elements and/or components may represent mechanical, electrical,fluid, optical, electromagnetic, wireless and other couplings and/orcombinations thereof. As used herein, “coupled” means associateddirectly as well as indirectly. For example, a member A may be directlyassociated with a member B, or may be indirectly associated therewith,e.g., via another member C. It will be understood that not allrelationships among the various disclosed elements are necessarilyrepresented. Accordingly, couplings other than those depicted in thedrawings may also exist. Dashed lines, if any, connecting blocksdesignating the various elements and/or components represent couplingssimilar in function and purpose to those represented by solid lines;however, couplings represented by the dashed lines may either beselectively provided or may relate to alternative examples of thepresent disclosure. Likewise, elements and/or components, if any,represented with dashed lines, indicate alternative examples of thepresent disclosure. One or more elements shown in solid and/or dashedlines may be omitted from a particular example without departing fromthe scope of the present disclosure. Environmental elements, if any, arerepresented with dotted lines. Virtual (imaginary) elements may also beshown for clarity. Those skilled in the art will appreciate that some ofthe features illustrated in the figures, may be combined in various wayswithout the need to include other features described in the figures,other drawing figures, and/or the accompanying disclosure, even thoughsuch combination or combinations are not explicitly illustrated herein.Similarly, additional features not limited to the examples presented,may be combined with some or all of the features shown and describedherein.

In FIG. 7 , referred to above, the blocks may represent operationsand/or portions thereof and lines connecting the various blocks do notimply any particular order or dependency of the operations or portionsthereof. Blocks represented by dashed lines indicate alternativeoperations and/or portions thereof. Dashed lines, if any, connecting thevarious blocks represent alternative dependencies of the operations orportions thereof. It will be understood that not all dependencies amongthe various disclosed operations are necessarily represented. FIG. 7 andthe accompanying disclosure describing the operations of the method(s)set forth herein should not be interpreted as necessarily determining asequence in which the operations are to be performed. Rather, althoughone illustrative order is indicated, it is to be understood that thesequence of the operations may be modified when appropriate.Accordingly, certain operations may be performed in a different order orsimultaneously. Additionally, those skilled in the art will appreciatethat not all operations described need be performed.

In the foregoing description, numerous specific details are set forth toprovide a thorough understanding of the disclosed concepts, which may bepracticed without some or all of these particulars. In other instances,details of known devices and/or processes have been omitted to avoidunnecessarily obscuring the disclosure. While some concepts will bedescribed in conjunction with specific examples, it will be understoodthat these examples are not intended to be limiting.

Unless otherwise indicated, the terms “first,” “second,” etc. are usedherein merely as labels, and are not intended to impose ordinal,positional, or hierarchical requirements on the items to which theseterms refer. Moreover, reference to, e.g., a “second” item does notrequire or preclude the existence of, e.g., a “first” or lower-numbereditem, and/or, e.g., a “third” or higher-numbered item.

Reference herein to “one example” means that one or more feature,structure, or characteristic described in connection with the example isincluded in at least one implementation. The phrase “one example” invarious places in the specification may or may not be referring to thesame example.

As used herein, a system, apparatus, structure, article, element,component, or hardware “configured to” perform a specified function isindeed capable of performing the specified function without anyalteration, rather than merely having potential to perform the specifiedfunction after further modification. In other words, the system,apparatus, structure, article, element, component, or hardware“configured to” perform a specified function is specifically selected,created, implemented, utilized, programmed, and/or designed for thepurpose of performing the specified function. As used herein,“configured to” denotes existing characteristics of a system, apparatus,structure, article, element, component, or hardware which enable thesystem, apparatus, structure, article, element, component, or hardwareto perform the specified function without further modification. Forpurposes of this disclosure, a system, apparatus, structure, article,element, component, or hardware described as being “configured to”perform a particular function may additionally or alternatively bedescribed as being “adapted to” and/or as being “operative to” performthat function.

Different examples of the apparatus(es) and method(s) disclosed hereininclude a variety of components, features, and functionalities. Itshould be understood that the various examples of the apparatus(es) andmethod(s) disclosed herein may include any of the components, features,and functionalities of any of the other examples of the apparatus(es)and method(s) disclosed herein in any combination, and all of suchpossibilities are intended to be within the scope of the presentdisclosure.

Many modifications of examples set forth herein will come to mind to oneskilled in the art to which the present disclosure pertains having thebenefit of the teachings presented in the foregoing descriptions and theassociated drawings.

Therefore, it is to be understood that the present disclosure is not tobe limited to the specific examples illustrated and that modificationsand other examples are intended to be included within the scope of theappended claims. Moreover, although the foregoing description and theassociated drawings describe examples of the present disclosure in thecontext of certain illustrative combinations of elements and/orfunctions, it should be appreciated that different combinations ofelements and/or functions may be provided by alternative implementationswithout departing from the scope of the appended claims. Accordingly,parenthetical reference numerals in the appended claims, if any, arepresented for illustrative purposes only and are not intended to limitthe scope of the claimed subject matter to the specific examplesprovided in the present disclosure.

What is claimed is:
 1. An aircraft comprising: a landing gear including:a shock strut; an outer sleeve at least partially surrounding the shockstrut; and a shrink mechanism coupled to both the outer sleeve and theshock strut, the shrink mechanism being configured to move the shockstrut relative to the outer sleeve, the shrink mechanism including: ashaft rotatably coupled to the outer sleeve about a shaft rotation axis,the shaft being disposed perpendicular to a centerline of the shockstrut, an anchor arm coupled to the shaft, the anchor arm beingconfigured to couple to a structure within a wing of the aircraft, ashrink arm coupled to the shaft, the shrink arm and the anchor arm beingcoupled to the shaft so as to rotate as a unit with the shaft about theshaft rotation axis, relative to the outer sleeve, at least 180° whenthe anchor arm is coupled to the structure within the wing of theaircraft, and a shrink link rotatably coupled to the shrink arm, theshrink link being configured to rotatably couple to the shock strut. 2.The aircraft of claim 1, wherein the anchor arm is coupled to thestructure with a rod.
 3. The aircraft of claim 1, wherein the shockstrut travels within the outer sleeve to extend and retract the landinggear.
 4. The aircraft of claim 1, wherein the shrink arm rotates aboutshaft rotation axis and wherein shrink link travels within the outersleeve to extend and retract the landing gear.
 5. The aircraft of claim1, wherein the outer sleeve is integrally formed with a landing geartrunnion and wherein the landing gear trunnion is rotatably coupled tothe wing.
 6. The aircraft of claim 1, wherein the anchor arm isconfigured to couple to a rear spar within the wing of the aircraft. 7.The aircraft of claim 1, wherein the structure within the wing isseparate and distinct from the landing gear.
 8. The aircraft of claim 1,further comprising a door coupled to the shrink arm, the door isconfigured to seal an opening in the outer sleeve with the landing gearin an extended position.
 9. The aircraft of claim 8, wherein the doorcomprises a hinged door configured to engage the outer sleeve forsealing the opening.
 10. The aircraft of claim 1, wherein the shrinklink mechanism is configured to act in a single plane that is transverseto a rotation axis of a landing gear trunnion of the landing gear.
 11. Alanding gear for use on an aircraft, the landing gear comprising: anouter sleeve having a cylindrical guide surface; a shock strutpositioned at least partially within the outer sleeve, the shock strutcomprising: an outer cylinder that is shaped and sized to engage thecylindrical guide surface where the cylindrical guide surface guidessliding movement of the outer cylinder relative to the outer sleeve, andwhere the outer cylinder is configured to couple with a shrink mechanismconfigured to drive the sliding movement of the outer cylinder, and aninner cylinder disposed at least partly within the unitary outercylinder; and an anti-rotation linkage comprising: a connector platecoupled to the outer cylinder of the shock strut, and an anti-rotationlink assembly coupled to both the outer sleeve and the connector plate,the anti-rotation link assembly being configured to maintain the shockstrut in a fixed rotational orientation relative to the outer sleeve.12. The landing gear of claim 11, wherein the anti-rotation linkassembly maintains wheels coupled to the shock strut in a predeterminedorientation relative to the outer sleeve.
 13. The landing gear of claim11, wherein the landing gear is a semi-levered landing gear having atruck link pivotally coupled to the connector plate and at least onewheel rotatably coupled to the truck link.
 14. The landing gear of claim13, wherein the inner cylinder is movable relative to the outercylinder.
 15. The landing gear of claim 14, wherein the truck link ispivotally coupled to both the connector plate and the inner cylinder ofthe shock strut.
 16. The landing gear of claim 11, wherein theanti-rotation link assembly comprises: a first scissors link coupled tothe outer sleeve; and a second scissors link coupled to both the firstscissors link and the connector plate to connect the outer sleeve to theshock strut.
 17. The landing gear of claim 11, further comprising: theshrink mechanism, where the shrink mechanism is coupled to both theouter sleeve and outer cylinder of the shock strut, the shrink mechanismcomprising: a shaft rotatably coupled to the outer sleeve about a shaftrotation axis, the shaft being disposed perpendicular to a centerline ofthe shock strut; an anchor arm coupled to the shaft, the anchor armbeing configured to couple to a structure within a wing of the aircraft;a shrink arm coupled to the shaft, the shrink arm and the anchor armbeing coupled to the shaft so as to rotate as a unit with the shaftabout the shaft rotation axis, relative to the outer sleeve, at least180° when the anchor arm is coupled to the structure within the wing ofthe aircraft; and a shrink link rotatably coupled to the shrink arm, theshrink link being configured to rotatably couple to the outer cylinderof the shock strut.
 18. The landing gear of claim 17, wherein the anchorarm is coupled to the structure with a rod.
 19. The landing gear ofclaim 17, wherein the shock strut travels within the outer sleeve toextend and retract the landing gear.
 20. The landing gear of claim 17,wherein the shrink arm rotates about the shaft rotation axis and theshrink link travels within the outer sleeve to extend and retract thelanding gear.